16alpha, 17alpha-dihydroxypregnen-20-ones and process for preparation of same



nited States Patent a 3,021,345 160:,17a-D1HYDROXYPREGNEN-20-ONES AND PROCESS FOR PREPARATION OF SAME Sheila M. Waddington-Feather (ue Booker), Bernard Ellis, and Vladimir Pen-ow, all of London, England, assignors to The British Drug Houses Limited No Drawing. Filed Sept. 19, 1960, Ser. No. 56,700 Claims priority, application Great Britain Sept. 24, 1959 Claims. (Cl. 260-3914) This invention is for improvements in or relating to the preparation of organic compounds and has particular reference to the preparation of l6a,17a-dihydroxypregnen- 20-one derivatives of the Formula I below, where R is a hydrogen atom or a methyl group.

It is an object of the present invention to provide a novel process for the preparation of 16u,l7a-dihydroxypregnen-ZO-ones of the Formula I below, where R is a hydrogen atom or a methyl group, which process is superior to known processes in that the yields of l6a,l7adihydroxypregnen-ZO-ones obtained are considerably higher, the experimental operations involved are simpler, the quantities of solvents employed are minimal and hence the process is more economical, and serious difiiculties are not encountered as the scale is increased.

It is a further object of this invention to provide the new steroidal derivative 6-methyl-3fl-l6u,17a-t1ihydroxypregn-5-en-20-one which is of value on account of its glucocorticoid and other biological properties and as an intermediate in the preparation of cyclic acetals and ketals with useful biological properties, e.g. progestational, antiinflammatory and diuretic activity. Thus for example by condensation with acetonein the presence of perchloric 'acid the corresponding l6a,l7a-acetonide may be prepared which passes. into the corresponding 3-oxo-A -6umethyl derivative by an oxidation of the Oppenauer type. The latter compound is a potent anti-inflammatory steroid which differs from known anti-inflammatory steroids in being devoid of .an ll-oxygenated function and it thus represents a new class of anti-inflammatory material which is active inter alia in dermatological conditions.

According to the present invention there is provided a process for the preparation of 3 B,l6oz,17oc-trihydroxypregn- S-en-ZO-ones having the general formula (where R is hydrogen or a methyl group) which process comprises reacting a l6a,17a-epoxypregnen-20-one having "ace (Where R has the same meaning as above and R is hydrogen or an aliphatic acyl radical containing from 1 to 8 carbon atoms) with an alkoxy carbonyl hydrazine and a lower alkanoic acid containing up to 3 carbon atoms to give the corresponding alkoxy carbonyl hydrazone of a 16u-alkanoyloxy-l7a-hydrQXypregnen-ZO-One, saponifying the alkoxy carbonyl hydrazone to give a l5a,l7udihydroxy derivative and hydrolysing the foregoing l6u,l7adihydroxy derivative to the required '35,l6u,l7atrihydroxypregn-S-en-ZO-one.

It is believed that the above-mentioned alkoxy carbonyl hydrazone of a l6a-alkanoyloxy-17a-hydroxypregnen-20- one has the formula (where R and R have the same meaning as'a'bove and R"'i's the 'alkyl group derived from the lower alkanoic acid containing up to 3 carbon atoms);

It is also believed that the above-mentioned 160;,17a-dihydroxy derivative has the formula (where R has the same meaning as above).

In carrying the process of the invention into effect, it has been found that conversion of a BB-acyloxyor 313- hydroxy-la,l7u-epoxypregn-5-en-20-one (II) into the corresponding alkoxycarbonylhydrazone of a l6u-alkanoyloxy-17a-hydroxypregn-S-en-ZO-one (Ill) is conveniently achieved by treating a solution of the Compound 11 in a lower alkanoic acid, such as acetic acid, with an'excess (preferably not less than 3 moles) of an alkoxycarbonylhydrazine, such as ethoxycarbonylhydrazine, and stirring the mixture at room temperature until reaction is complete. Thereafter the mixture is poured into water and the precipitated product collected, washed and dried. The material so obtained is sufiiciently pure for use in the next stage, but may he purified by recrystallisation if desired. Saponification may be accomplished by heating the foregoing product with ethanolic or methanolic sodium or potassium hydroxide, the 16,17a-dihydroxy derivative (IV) being obtained after acidification with, for example, acetic acid and dilution of the mixture with water. The material obtained in this way is sufl'iciently pure for use in the next stage, but may be purified if desired. Conversion of the l6a,l7a-dihydroxy derivative (IV) into Compound I may be achieved by treating Compound IV with a mixture of aqueous acetic acid and not less than 1.2 molar proportions of pyruvic acid EXAMPLE 1 313,16a,]7a-trihydroxypregn-5-en-20-0ne (l; R=H) (a) Ethoxycarbonyl hydrazine (238.5 g.) was added to a solution of 3B-hydroxy-16a,17a-epoxypregn-5-en-20- one (238.5 g.) in acetic acid (2 l.) and the mixture stirred at room temperature for 18 hours. A marked increase of viscosity occurred after the first 4 hours of stirring. This was followed by a decrease in viscosity during the next 2 hours and the separation of a fine granular solid. The mixture was poured slowly with stirring into a solution of sodium chloride (350 g.) in water (10 l.) at C., and the precipitated solids collected, washed with water'and pressed dry.

' A solution of the foregoing product in methanol (2.3 1.) containing potassium hydroxide (37.5 'g.) was heated under reflux for 20 minutes. The mixture was then treated with acetic acid (50 ml.) and poured into cold water (12. 1.). The product was collected, washed and pressed dry. A stirred solution of the foregoing material in acetic acid (1240 ml.) at 100 C. was treated with pyruvic acid (94. ml.). Ten minutes later, water (800 ml.) was added over a period of 5 'to minutes, and the heating and stirring continued for a further 20 minutes. The mixture was then cooled to room temperature and the product collected by filtration, washed with water and dried to give 35,16d,17a-trihydroxypregn-5-en-20-one, M.P. 240 to 245" C.,' not depressed in admixture with an authentic specimen.

(b) 3 3 acetoxy-16a,17o -epoxypregn-5-en-20-one was reacted with ethoxycarbonyl hydrazine in acetic acid and the product processedexactly as described in Example 1(a). There was obtained 3,6,16a,17a-trihydroxypregn- 5-en-20-one, M.P. 242 to 247 C., identical in every respect with an authentic specimen. 7 l

V EXAMPLEVZ I V ti -m ethyl-33,160:,17a-trihydroxypregn-S-eri-Z0 0ne A solution-of 3p-hydroxy-16a,17a epoxy-6 -methylpregn-S-ZO-one (45.6 g.) in acetic acid (400 ml.) was treated with ethoxycarbonylhydrazine (45.6 g.) and the mixture stirred at room temperature for 8 hours. After being set'aside overnight, the mixture was poured into a solution of sodium chloride (450 g.) in water (2.7 1.), and the precipitated solids collected, washed, and dried at 100 Cato give material with M.P. 220 to 240 C. Purification from aqueous methanol gave needles, M.P. 250.to.252' C. (decomp.), [ch 128 (c, 0.93 in chloroform). I a

The foregoing compound (57 g.) in ethanol (400 ml.) containing sodium hydroxide (7 g.) was, heated under refiuxzfor' 30 minutes. The mixture was then treated withacetic acid (12 ml.) and poured into cold water.

lected, washed and purified from aqueous ethanol to give 6-methyl-3B,16a,l7a-trihydroxypregn-S-en-ZO-one in fiat needles, M.P. 213 to 215 C., 65 (c, 1.0 in chloroform containing a trace of pyridine).

We claim:

1. A process for the preparation of 3p,16a,17a-trihydroxypregn-S-en-ZO-ones having the general formula where R has the same meaning as above and R is selected from the class consisting of hydrogen and an aliphatic acyl radical containing from 1 to 8 carbon atoms, with an alkoxy carbonyl hydrazine and a lower alkanoic acid containing up to 3 carbon atoms to give the corresponding alkoxy carbonyl hydrazone of-a l6u-alkanoyl- OXY-17u-i1ydI0XYpleglleIl-ZO-OIIC, saponifying the alkoxy carbonylhydrazone to give a l6a,l7a-dihydroxy derivative and hydrolysingthe foregoing 16a,l7a-dihydroxy derivative by treatment with a mixture of acetic acid and not less than 1.2;molarproportions of pyruvic acid to the required 313,l6a,17a-trihydroxypregn-5-en-20-one.

2. A process as claimed in claim 1 wherein a solution of the 16a,17u-epoxypregnen-20-one in alower alkanoic acid is treated with an excess of the alkoxycarbonylhydrazine.

3. A process as claimed in claim 2 wherein a solution of the 16a,17a-epoxypregnen-20-one in acetic acid is treated with at least 3'moles of ethoxycarbonylhydrazine.

4. A process as claimed in claim l'wherein the saponification is effected by heating with ethanolic or methanolic 1 sodium or potassium hydroxide.

The product was collected, washed with water and dried.

was added'dropwise until a crystalline solid separated.

After cooling to room temperature,the product was col- 5. Aprocess for the preparation of 3,3,16a,17-trihydroxy-pregn-S-en-ZO-ones having the general formula:

where R is selected from the group consisting of hydrogen and methyl, which process comprises saponifying an alkoxy carbonyl hydrazone having the formula:

where R has the same meaning as above, R is selected 6 from the group consisting of hydrogen and an aliphatic acyl radical containing from 1 to 8 carbon atoms and R is an alkyl group containing up to 3 carbon atoms, to give a 16u,17a-dihydroxy derivative and hydrolyzing the foregoing 16u,17a-dihydroxy derivative by treatment with a mixture of acetic acid and not less than 1.2 molar proportions of pyruvic acid to the required 3p,16u,17- trihydroxy-pregn-5-en-20-one.

References Cited in the file of this patent UNITED STATES PATENTS 2,808,399 Dodson Oct. 1, 195'] 2,894,961 Dodson July 14, 1959 

1. A PROCESS FOR THE PREPARTION OF 3B, 16A, 17A-TRIHYDROXYPREGN-5-EN-20-ONES HAVING THE GENERAL FORMULA 